Pancake domes on Venus

. These seven volcanic domes were discovered in Magellan's radar images. They all have round shapes that are about 25 thousand meters across, and steep sides that are less than 750 meters high. Their central vents may be lined up along a crack in the surface. These domes are interpreted as very thick, stiff and sluggish lava flows, rather than the fluid and runny type. Eruptions of the pasty, viscous lava, coming from a central vent on a relatively level surface, would form the circular, flattened shapes that resemble giant pancakes. Since there is little or no erosion by wind or water on Venus, newer pancakes look much the same as the ones on which they are superimposed. (Courtesy of JPL and NASA.)